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J. P. OROURKE. GAISSON SHAFT.

(No Model.)

No. 591,632. Patented Oct. 12,1897.

W/ TNE SSE S ATTORNEY.

ETERS w Puo'muma. WASNING UNITED- STATES PATENT OFFICE.

JOHN F. OROURKE, OF NEW YORK, N. Y., ASSIGN OR TO STEPHENS & OROURKE, OF SAME PLACE.

CAISSON-SHAFT.

SPECIFICATION forming part of Letters Patent No. 591,632, dated October 897. Application filed January 28, 1897. Serial No. 620,996. (No model.)

To all whom it may concern.-

Be it known that I, JOHN F. OROURKE, of New York, in the county and State of New York, have invented certain new and useful Improvements in Caisson-Shafts, of which the following is a full, clear, and exact description.

My invention relates to improvements in the construction of the shafts of caissons and analogous shafts. In structures of this kind where buckets, cages, or other devices are arranged to move up and down the shaft it is necessary that the shaft have an entirely unobstructed interior and that the walls be left practically plain, so that nothing can catch on the shaft and thereby cause damage or accident. It is also known that in caissons and similar apparatus bad accidents and attendant loss of life frequently ensue as the result of a sudden filling of the caisson or some similar accident which makes it necessary for the people in the caisson to escape into the shaft. Quite frequently if it were possible for the'men to get into the shaft and even partially ascend, so as to get above the waterlevel, they would be'saved.

The object of my invention is to construct a shaft with a ready means of escape, so that in case the bucket or cage cannot be reached the men can scramble up the sides of the shaft and quickly reach a place of safety. Such shafts usually contain air under pressure; and another object of my invention is to construct the safety apparatus in such a way that air cannot escape, and, further, to construct it in such a way that the shaft will not be weakened and its cost not very materially increased.

IVith these ends in view my invention consists of a caisson or other shaft the construction of which will be hereinafter fully described and claimed.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar figures of reference indicate corresponding parts in all the views.

Figure 1 is a broken side elevation, partly in section, of a shaft showing my improvements. Fig. 2 is a front elevation of the shaft and my improved ladder attachment, a part of the ladder-cover being shown in vertical cross-section. Fig. 3 is a broken sectional plan of the shaft. Fig. 4 is a broken front elevation of a slightly-modified form of the shaft, and Fig. 5 is a broken sectional plan of the shaft shown in Fig. 4.

The shaft 10 is of metal and may be either sectional or made in a single length. In fact, it can be made in any usual way without in the least afiectin g the principle of my invention. In the side wall of the shaft is cut a series of transverse slots 11, arranged one above another and a convenient distance apart to enable a person tostep from one to the other, the slots being of a size to easily receive the foot or hand of a person ascending or descending the shaft, and consequently the series of slots form a ladder, no part of which projects into the interior of the shaft. The air would ordinarily escape through the slots, and to prevent this they are provided with a cover 13 of the same material as the shaft, which bulges outward, so that there is sufficient distance between the cover and the slots 11 to permit the insertion of a foot or hand in the slot without inconvenience, and this cover extends the full length of the shaft and is riveted or otherwise fastened at the edges, as shown at 13, while to prevent it from bulging under the air-pressure or from being forced inward by any ordinary accident it is stayed by the bolts 14, which extend through the cover and into the shell of the shaft 10. At the top and bottom the cover is bent inward and riveted or bolted to the shaft, as shown at 15, the drawings showing the top only, but the bottom is precisely the same, so that there is no necessity of showing it.

In Figs. 4 and 5 I have shown a slightlydiiferent arrangement, in which the cover instead of being bent inward at the top, as described above, is straight vertically and has the space between itself and the shaft 10 filled by a block or casting 16,which is firmlybolted, as shown at 17, to the cover and shaft.

It will of course be understood that the shaft may be provided with any necessary number of ladders, such as described, and it will'be equally evident that the cover 12 may claim as new and desire to secure by Letters Patent- 1. The combination with the shaft, of a ladder formed by slotting the shaft, and an air seal for the slots whereby the escape of air from the shaft is prevented, substantially as described.

2. The combination with the shaft and the ladder-slots therein, of an external cover for the slots, said cover being secured to the shaft so as to form an air seal, substantially as described.

3. The combination with the shaft, adapted to permit the passage of a bucket, cage or similar article, of the ladder sunk in the side of the shaft, whereby the wall of the latter is left essentially plain.

4. The combination with the shaft and the ladder-slots therein, of the bulging cover extending the full length of the ladder formed by the slots, said cover being secured at its edges to the shaft, substantially as described. 35

JOHN F. OROURKE.

\Vitnesses:

W. B. HUToHINsoN, BERTHA DEYO. 

